The role of collectivisation in the Soviet famines of the early 1930s is obviously a contentious issue and deeply intertwined with the question of intention. I’d recommend that before reading on, you have a look at this quick summary of the key positions from /u/Smilin_Dave.

However, within Western academia – ie ignoring apologist pseudo-historians like Grover Furr – there is broad consensus that collectivisation played a significant role in the famines. (I also won't spend time on Robert Conquest, who sees collectivisation as a straightforward tool for the 'terror-famine'.) The most notable dissenting voice is probably Mark Tauger. In essence (read: simplifying massively) Tauger argues that farming was collectivised before the famine, farming was collectivised after the famine and therefore something else must have happened during the famine. He therefore places the blame on the shifting weather.

There’s a degree of truth in this – the 1929/30 harvest, for example, was a considerable success despite the absolute chaos of collectivisation – but I don’t necessarily agree with Tauger, preferring instead the analysis of Davies and Wheatcroft (The Years of Hunger). They instead posit four key causes for the 1932-33 famine:

• Over-extension of the sown area. There was intense pressure from above to sow more land than before (which was achieved). This was achieved at a decrease in fallow land and in many areas a vanishing of crop rotation entirely.

• Collapse in livestock numbers. Since the onset of collectivisation the peasantry had been slaughtering their animals, due to a lack of fodder or a reluctance to see them ‘socialised’ by the collective farm. This was particularly damaging in terms of horses, who provided much of the draught power for the sowing. The limited appearance of tractors failed to compensate for this: available draught power in 1932 was just over two-thirds of the 1928 figure.

• Poor quality of cultivation. Both of the above contributed to the quality of the fieldwork in those years. Peasants were demoralised, operating without adequate tools, coping with contradictory instructions from above, etc. This provided the most obvious results of the harvest: fields overgrown with weeds, inadequately sowed and harvested, collected grain rotting in poor storage, etc.

• The weather. This was always a key factor in any harvest – it lay behind the poor collections of 1927-28 and saved the harvest of 1929/30 from its chaotic preparations. Such fluctuations are also particularly acute in the Producer Regions of the USSR. In 1932 there was the particularly poor combination of hot draught weather followed by heavy rain.

Of these factors that Davies and Wheatcroft point to, three of them are directly related to collectivisation. They represent the cumulative impact of years of botched reforms and chaotic planning in the agricultural sphere by the state. It took poor weather to tip a poor harvest into a disastrous one but the conditions for this famine were a product of Soviet agricultural policy.

Or, as Davies put it way back in 1980, "the policy of the Soviet government, which gambled every year that the harvest in the year concerned would be a good one, was inherently unrealistic" (The Socialist Offensive). In 1932-33 this gamble failed and the chaos of collectivisation caught up with Soviet agriculture.